Electro-hydraulic control structure



y 1936} 1.7 M. PERSONS 2,040,403

ELECTRO HYDRAULIC CONTROL STRUCTURE Filed Jan. 51; 1934 Patented May 12, 1936 PATENT OFFICE ELECTED-HYDRAULIC CONTROL STRUCTURE Lawrence M. Persons, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines, Iowa,

a corporation of Iowa Application January 31,}934, Serial No. 709,201

1 Claim.

The object of my invention is to provide an electric control structure which is simple, durable and comparatively inexpensive to manufacture, the present application being a continuation in 5 part of my co-pending application" Serial No. 631,892 filed September 6,- 1932 now Patent No. 2,020,618.

A further object is to provide a control structure electrically operated for the purpose of open- 10 ing a valve or operating other controlling devices whenever energized, said structure upon being deenergized allowing said valve or other device to return to its initial position.

still a further object is to provide in combina- 15 tion with a controlling device constrained to remain in one position, means for moving it to an opposite position whenever such means is energized and for maintaining the controlling device in such opposite position until deenergization of the 10 means so that the controlling device can then be returned to its first position because of being constrained toward such position. i

Still a further object is to provide a controlling device and means for moving it from one'position to another comprising an expansible pressure chamber-in operative connection with the controlling device and an electrically operated pump for supplying fluid pressure to the pressure chamher, the controlling devicebeing arranged with stop means so that when it assumes a position because of expansion of the pr essure chamber the pump can continue to operateibecause of the slippage of the medium supplied to the pressure chamber relative to the pump so that when an 0 electric motor is used for operating the pump it will then continue to operate as long as energized, the continuing operation being at a relatively low speed but not stalling the motor.

Still a further object is to provide a connection between an oil pump and a controlling device which includes a movable member automatically operable to permit by-passing of the oil from the controlling member around the pump when return movement of the controlling member occurs.

Still a further object is to provide a control device comprising a valve, the valve plug of which is resiliently mounted in such manner that snap action is secured during the closing and J opening movements of the valve. 7

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my device, whereby the objects contemplated are at-- tained, as hereinafter more fully set forth, pointed out in my claim and illustrated in the accom panying drawing, in which:

Figure l is a side elevation of an electric control structure embodying my invention.

Figure 2 is an enlarged vertical sectional view 5 of the same.

Figure 3 is a sectional view of a portion of Figure 2 showing the parts in a different position; and

Figure 4 is a sectional view of a portion of Figure 2 on a reduced scale showing the valve in a different position.

On the accompanying drawing I have used the reference character A to indicate a gas valve. This valve may be used in connection with gas furnaces or the like for controlling the supply of gas thereto, although instead of being a gas valve it can be any other control device adapted to be moved to opposite positions by the electric mechanism B which I provide for operating the valve A.

The valve A includes a body l0 having an inlet l2 and an outlet I4. Between the inlet and the outlet a seat I6 is provided against which a valve disc I8 is adapted to seat.

For actuating the valve disc l8 to closed position I provide a spring 20 interposed between a packing 22 and piston 24. The piston 24 is mounted on a valve stem 26 which in turn is connected with the valve'disc I8. The manner of connection is by means of a pin 21 extending across a socketed boss 28 of the valve disc I8 and through a slot 30 of the upper end of the valve stem which end is received in the socket of the boss 28. A spring 32 is interposed between the boss 28 and a cover cup 34, resting against 35 a shoulder of the valve stem 26.

The piston 24 is reciprocable in a cylinder 36, the piston and cylinder forming an expansible pressure chamber. Beneath the cylinder 36 is an electric motor having field laminations 38 40 and armature laminations 40. Field coils are indicated at 42 and the motor is preferably of the shaded pole type so that it can be either stalled or its speed cut to a minimum without harming the motor, even though it remains 45 energized. The armature 40 is secured to a shaft 44 which has an oil-center crank pin 46. A pump is provided in the form of radially extending cylinde s 48 having pistons 50 therein. Wrist pins 50 52 extend from the pistons 50 and are connected by connecting rods 54 to pins 56 of discs 58. The discs are pivoted on the crank pin 46, the entire pump structure being fully disclosed in my Patent No. 2,020,618 above referred to. 55

' when the motor and pump are operated, flows through an intake port 68 in the shaft 44 to the cylinders 48 when the pistons travel outwardly therein. An outlet port 18 provides for escape of the. oil from the cylinders when the pistons move inwardly, this oil escaping as indicated by the arrows into the pump casing 64.

The pumped oil flows through a passageway I2 to a by-pass valve plug I4 slidable in a bore I5 and opens a check valve 16 therein and then flowing through a passageway I8 to the cylinder 36. The check valve I6, however, is not opened until the plug I4 is slid toward the left to seat against a valve seat I9 and thereby plug up a by-pass port 88 as shown in Figure 2.

The cylinder 36 may be provided with a port 31 through which the oil may return to the reservoir 62 if this type of construction is desirable.

Practical operation This control structure is adapted for use in connection with a room thermostat or other controlling device whereby when the room thermostat calls for heat it energizes the motor for opening the valve disc I8 and permitting gas to flow to the furnace to augment the fire. The spring 28 returns the valve disc to closed position when the motor is de-energized, caused by the heat requirements of the thermostat being satisfied.

Upon energization of the motor, the oil 66 normally within the reservoir casing 62 is pumped, as indicated by the arrows in Figure 2, to first close the by-pass port 88 by moving the plug 14 in the bore 15 toward the left and then the pressure is built up until the spring closed check valve 16 is opened so that the oil can fiow into the pressure chamber to raise the piston The valve disc I8 will first be in the full line position of Figure 4 and after the piston 24 and the valve stem 26 are raised the spring 32 will be compressed, the pin 21 and the slot 38 permitting lost motion. The valve disc I8 will re.- main seated, due to the pressure of the incoming gas until the bottom of the slot 38 engages the pin 21 and raises the valve disc slightly. The gas will then rush under the disc. This, together with the expanding tendency of the spring 32 will quickly snap the disc to a substantially open4 position as shown by dotted lines in Figure The piston 24 will continue to rise until the valve is wide open, whereupon it will be stopped in the position of Figure 2 by the spring 28 being closed, or some other mechanical stop means, and thereafter the motor will operate at a much slower speed, depending upon how much slippage of oil there is through the pump.

The port 31 is optional. If it is used, then of course the oil beneath the piston 24 will fiow through it when the piston rises high enough to uncover this port. This will prevent any further upward movement of the piston and the motor can still rotate at the same speed if the port is large enough, or at a somewhat reduced speed if the area of the port is small enough to offer more resistance of the flow of spring 28 does to the travel of the piston 24.

When the motor is de-energized, the oil pressure in the passageway I2 will be reduced by the slippage of oil through the pump and the spring 20 will operate to first push the plug 14 toward the right and against a stop 11, as in Figure 3, and then to quickly expel the oil from beneath the piston 24 through the by-pass port 88 into,

the reservoir 62. The valve disc I8 will first assume the dotted line position of Figure 4 and soon thereafter the rush of gas through the valve seat I8 will cause the disc to seat with a snap action compressing the spring 32 as shown by full lines in Figure 4 and soon after this the valve stem 26 will have reached itslower limit of movement.

The automatically operable valve plug 14 permirs a much quicker return of the oil than if it were permitted to leak slowly through-the clearance spaces in the pump. As soon as the oil starts to return, the by-pass port 88 is open so that the movement of the returning oil is then unimpeded.

Some changes may be made in the construc- I tion and arrangement of the parts of my device without departing from the real spirit and purpose of my invention,'and it is my intention to cover by my claim, any modified forms of structure or use of mechanical equivalents, which may be reasonably included-within their scope.

I claim as my invention:

. In a control structure, a controlling device movable to opposite positions, means constraining said device to remain in one of said positions and .mechanism to move said controlling device to its opposite position against such constraint, said mechanism comprising a pressure chamber, a medium therein, said pressure chamber being in operative connection with said controlling device to move it to such opposite position upon said medium being placed under pressure, a reservoir, a pump having an intake connected with said reservoir and an outlet .connected with said pressure chamber, said last connection including a bore having a stop at one end and a valve seat at its other end, communicating with said reservoir and a movable member therein adapted to be moved toward said valve seat by the medium as it passes through said bore and to engage and close said valve seat, said movable member when in an opposite position engaging said stop and permitting return of said medium from said pressure chamber to said reservoir through said valve seat, said member when in said first position preventing such passage of said medium, check valve means in said member for permitting restricted flow only of the medium from the pump to the pressure chamber when said member is in said first position, means for stopping the movement of said controlling device when it assumes its opposite position, and means for operating said pump to place said medium under pressure, said last named means when inoperative allowing the pressure of said medium to reduce and said movable member to thereby be moved by said constraining means away from said valve seat to permit return of said medium.

LAWRENCE M. PERSONS. 1

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